Drug abuse, HIV/AIDS, and violence are all critical public health problems in the lives of impoverished housed and homeless women. However, the relationships among drug abuse, other behaviors that place women at risk for HIV.AIDS (i.e., unprotected sex and sharing of needles and works), and violence (i.e., physical and sexual victimization) remain unclear. Further, there is a lack of research on the impact these interrelated problems have on health outcomes (i.e., physical health and injuries, service utilization, and psychological distress) for homeless and low-income housed women. The goal of this study is to examine the linkages among drug abuse, other HIV risk behaviors, and violence, and to determine their impacts on key health outcomes (physical health and injuries, service utilization, and psychological distress) among homeless and low-income housed women in Los Angeles County. In this natural history study, 840 primarily African-American, Latina, and Caucasian women between the ages of 18 and 62 residing in randomly selected homeless shelters and low-income housing units will be administered structured interviews and will undergo physical health assessments at baseline and at 12-month follow-up. For a sub-sample of 20% of the women, hair samples will be collected to validate self-reported drug use. In-depth interviews (30 with homeless women, 30 with low-income housed women) will precede structured interviews and physical health assessments to ensure inclusion of important measurement domains and validity of instruments, particularly those addressing victimization. Focus groups (2 with homeless women, 2 with housed women, 2 with community experts, and 2 with policy makers) will be conducted at the end of the study to help us frame results in terms of feasible community and policy interventions for homeless and low-income housed women. The specific aims of this study are: 1) determine correlates of, and examine linkages between, drug abuse, HIV risk behaviors, and victimization among low-income housed and homeless women, 2) prospectively determine the impact that drug abuse, HIV risk behaviors, and victimization have upon key health outcomes (physical health and injuries, service utilization, and psychological distress), 3) document low-income housed and homeless women's understanding of and experiences with victimization.